His body was taken to the Cook County morgue on July 22, 1934 - a mystery fueled by the fact that the official autopsy report went missing for 50 years.
Dillinger left behind a tommy gun that he usually carried. After all, he was on a date that Sunday night with his girlfriend, Polly Hamilton.
Federal agents had received a tip that the couple would be at the Biograph and had even sketched out a deployment plan to grab Dillinger on the way out, according to the bank robber's great nephew, just in time.
"He had actually planned on leaving that week that he was going to go to South America. He had one more job to do, it was a train robbery, and he was going to be heading to South America and his plan was to take the entire family," said Jeff Scalf, Dillinger's great nephew.
But this would be his last trip walking out of the Biograph.
Police reports said he went for a pistol from his pant's pocket as he ran toward a Lincoln Avenue alley. A cordon of officers opened fire, dropping Dillinger just before 11 p.m.
FBI files show that Dillinger was decked out his final night in white bucks, red garters and a matching necktie.
The body was taken to the Cook County morgue for an autopsy. But some witnesses reported that it didn't look like Dillinger. They suggested that the g-men were trying to end public panic by merely saying they killed Dillinger when it was actually someone else.
The FBI denied it but when the autopsy report vanished the rumors persisted for decades until the autopsy paperwork turned up 50 years later in 1984.
An office worker rummaging through some old records found it in a shopping bag stuffed into a corner at the old county morgue.
The late I-Team producer John O'Brien obtained a copy for our files. The post-mortem report - called a coroner's protocol back then - provided the details of numerous gunshots Dillinger suffered and his various scars, injuries and signs of illnesses, even the ingredients of his last meal.
But the corpses' brown eye color did nothing to stop the rumors and speculation. Dillinger was known to have blue or gray eyes.
Then-Cook County medical examiner Dr. Robert Stein said that the eyes become cloudy after death and that color is sometimes hard to determine.
"It was rushed, it was very hectic that night. John was a legendary figure, and so I think there were some mistakes made. When I was younger, I wanted to believe that he got away, that it wasn't him, but it was him," said Scalf.
Those who viewed Dillinger's body at the morgue - even the bank robber's own father might not have recognized him. He had been shot in one side of his face and he had undergone plastic surgery to cover up some scars and alter his appearance.
When the Public Enemies movie opens a week from Wednesday, history will have determined its ending-a hail of bullets. As the I-Team found, what happened after Dillinger died may actually be the better story.
Web site of Jeff Scalf/Dillinger's great nephew: www.johndillinger.com
John Dillinger Museum inside the Indiana Welcome Center in Hammond, IN: http://www.dillingermuseum.com/
Click here to see the Biograph stake out plan - Melvin Purvis, Special Agent in Charge of the Chicago FBI Office drew this plan of where his agents would be stationed while staking out John Dillinger on his last day.
Click here to see Dillinger's autopsy - Dillinger's post-mortem by a doctor at the Cook County Morgue.
Click here to read the FBI Dillinger death mask investigation - Read the investigation into the pandemonium at Cook County's morgue following Dillinger's demise. "Every politician and his friend in Chicago crowded into the morgue for the morbid purpose of viewing Dillinger's remains," states the report that reveals how the deputy coroner accepted bribes to allow the unofficial viewings and the making of the death masks.